Convert seconds to nanoseconds for juju.unit.run

The juju.unit.run docstring does not specify what units the timeout
value should be in. This led to issue juju#225. Having looked into it,
juju is expecting it to be in nanoseconds. I don't think
nanoseconds is particularly intuitive so I have updated the function
to take the timeout in seconds and convert it internally to
nanoseconds.

I appreciate this is a breaking change for anyone currently specifying
the timeout in nanoseconds so I would quite understand if this change
is nack'd in which case I will submit a subsequent pr which simply
updates the doc string. Closes juju#225.

juju/unit.py

@@ -122,7 +122,7 @@ async def run(self, command, timeout=None):
         """Run command on this unit.
 
         :param str command: The command to run
-        :param int timeout: Time to wait before command is considered failed
+        :param int timeout: Time, in seconds, to wait before command is considered failed
         :returns: A :class:`juju.action.Action` instance.
 
         """
@@ -131,6 +131,10 @@ async def run(self, command, timeout=None):
         log.debug(
             'Running `%s` on %s', command, self.name)
 
+        if timeout:
+            # Convert seconds to nanoseconds
+            timeout = timeout * 1000000000
+
         res = await action.Run(
             [],
             command,

tests/integration/test_unit.py

@@ -25,6 +25,18 @@ async def test_run(event_loop):
             assert 'Stdout' in action.results
             break
 
+        for unit in app.units:
+            action = await unit.run('sleep 1', timeout=0.5)
+            assert isinstance(action, Action)
+            assert action.status == 'failed'
+            break
+
+        for unit in app.units:
+            action = await unit.run('sleep 0.5', timeout=2)
+            assert isinstance(action, Action)
+            assert action.status == 'completed'
+            break
+
 
 @base.bootstrapped
 @pytest.mark.asyncio